This invention relates to packaging for foods or other perishable commodities, and more specifically to such packaging provided with printed information such as date codes which is protected against damage from water, abrasion or tampering. The invention also provides packages bearing protected inscriptions relating to specific packages and their contents.
The use of date codes on food products and other perishable items has become commonplace. Generally such date. codes are printed on the product. Unfortunately, occurrences have been noted of tampering or alteration of date codes by unscrupulous individuals. Problems may also arise due to abrasion against the package during handling or transportation which may obscure the printing. More importantly, in the case of food packaging, it is important, also, to avoid contact between the ink and the packaged foods. Thus, there has been a need for processes to apply printing in more permanent fashion or, otherwise, to render the printed information tamperproof.
Additionally, printing may be applied to packaging for providing bar codes, for example, to provide pricing information. Also, printing may be applied using ink invisible under ambient lighting but which is visible using light of a special frequency.
Yet another situation in which problems are encountered is in the case of packaging together of multiple food ingredients, for example, prepackaged salads where individual packets of meat or cheese may be included in an overall package which contains moist produce such as lettuce. In this case, moisture on the produce may wipe away or distort any printing on the outside of the packets. It is, of course necessary that any such printing be done with food grade, inks. Such inks, however, are not permanent, However, heretofore, satisfactory methods for preventing the distortion and other aforementioned problems have been lacking.
The present invention provides an improved process for applying and securing imprints such as date codes to packages for containing perishable products in a manner that renders them virtually tamperproof and avoids the other above-enumerated problems encountered in the prior art. In accordance with an important aspect of the invention, such imprints are applied between sealed layers of a package. In accordance with a related aspect, the date codes or other imprints are covered by a layer of transparent packaging material so that the date codes remain visible but are tamperproof and moisture and abrasion resistant. Such imprints may contain information about the source of the goods. For example, identification of a packaging plant or specific production line or batch, may be imprinted on each package.
In accordance with a further related aspect, the packages are formed, in accordance with the invention, utilizing readily available packaging equipment. In an important embodiment of the invention, the equipment is of the form, fill and seal type. The process of this invention is especially. adapted to the use of vertical form, fill and seal packaging equipment used for packaging perishable foods such as cheese, meats, etc.
Any commercially available packaging equipment, such as form, fill and seal equipment may be used in the practice of the invention. Examples form, fill and seal equipment are those described in great detail, for example, in U.S. Pat. Nos. 4,288,965, 4,532,753, 4,884,387, 5,255,497,. 5,377,474, 5,485,712, 5,715,656, 5,752,370 and 5,852,920, which disclosures are incorporated by reference herein.
Briefly, the invention provides a process for packaging perishable products while providing tamperproof, water and abrasion resistant visible imprints such as date codes on the resultant packages. A preferred process of the invention includes the steps of providing form, fill and seal package making process equipment; and providing to that equipment a supply of plastic film in strip form having opposed first and second lateral edges and a thermally sealable side. An imprint is applied adjacent to a first edge on the sealable side. The film is then conveyed through a folding device to cause the printed date code to be overlaid. by the opposite or second lateral edge of the plastic film. The lateral edges of the film are then thermally sealed together with the second edge overlying the imprinted area adjacent to the first edge, thereby forming a thin walled plastic tube. The tube is then formed into a series of individual packages which are filled with the perishable product and sealed. The protected date code or other imprint is then visible through the transparent, sealed packaging material either under ambient light conditions or by the use of light of a special frequency.
In one embodiment, the tube is formed with a fin type seal. In this manner the opposite edges of the sealable side are thermally sealed together. However, an overlapping type seal may be formed instead, if desired. Sealing of the tube into individual packages and severing the packages from the tube results in packages containing a perishable product, such as comminuted cheese, within a plastic film package having fin type seals on three sides, with a tamperproof date code contained between the sealed-together layers of one of the seals. In other cases such seals may be formed on all four sides of the packages.
In accordance with a further aspect of the invention, there is provided a sealed package enclosing specific product wherein the package is imprinted with information relating to that specific product with the imprint being protected in accordance with the invention.
A polymeric plastic layer having a transparent portion forms at least one exterior surface of the container, the transparent portion being bonded at an interface to a substrate of the package. The substrate may be a portion of the same polymeric film or a separate element, for example, a plastic cup which also forms a part of the final sealed container. An inscription formed in the interface is protected by and viewable through the transparent portion, the inscription providing information relating specifically to the individual sealed package and the specific product contents enclosed therein.
Further aspects and objects of the invention will be apparent from the appended claims, the following detailed description and the drawings.